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This paper records some features of Red deer (Cervus elaphus L.) at very high population density on a Scottish island. About half the total population was shot-out in autumn 1974, and half the remainder in autumn 1975, with special searches for deer which had died of natural causes during the intervening year. In all, the animals examined amounted to 80% of the original population, and from the data gathered it was possible to (i) assess the structure and reproductive features of the original population; (ii) examine the level of animal performance at this exceptionally high population-density; and (iii) check for any changes in performance arising from the initial reduction in density.

The sex-ratio of adults in the original population showed a small excess of hinds, stags being apparently subject to a higher mortality rate than hinds after about six years of age. In performance, these deer were much the same as those living elsewhere on Scottish hill-land at relatively high population-density, i.e. with delayed puberty and poor breeding rates in hinds, and with much smaller adults than in woodland habitats. But, contrary to expectation, the general level of performance was not unusually low for Red deer on Scottish hill-land, and there was no evidence of transmissible diseases or excessive parasitism. It was also surprising that the animals showed no improvements in performance following their first reduction; if anything, they were slightly poorer after one year at reduced density. This may have been a temporary consequence of the severe disruption of existing behaviour patterns brought about by the sudden loss of many groups of deer.